Alliteration is a literary device when a series of words have the same first consonant sound. These sequence of words can be in a row or just close together. Alliteration provides rhythm and flow to the writing, which is why it is often used for poetry.  Alliteration can be used rhetorically as a mode to help the reader remember important parts in the passage due to the repeating consonant sounds. The repetition of  in marketing makes brand names and commercials easier to remember.

Example: “Deep into that darkness peering, long I stood there wondering, fearing, doubting, dreaming dreams, no mortal ever dared to dream before.”

The Raven by Edgar Allen Poe

The picture above depicts alliteration because of the repetition of the letter "p" at the beginning of each word.